/* *  TAP-Win32 -- A kernel driver to provide virtual tap device functionality *               on Windows.  Originally derived from the CIPE-Win32 *               project by Damion K. Wilson, with extensive modifications by *               James Yonan. * *  All source code which derives from the CIPE-Win32 project is *  Copyright (C) Damion K. Wilson, 2003, and is released under the *  GPL version 2 (see below). * *  All other source code is Copyright (C) 2002-2005 OpenVPN Solutions LLC, *  and is released under the GPL version 2 (see below). * *  This program is free software; you can redistribute it and/or modify *  it under the terms of the GNU General Public License version 2 *  as published by the Free Software Foundation. * *  This program is distributed in the hope that it will be useful, *  but WITHOUT ANY WARRANTY; without even the implied warranty of *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the *  GNU General Public License for more details. * *  You should have received a copy of the GNU General Public License *  along with this program (see the file COPYING included with this *  distribution); if not, write to the Free Software Foundation, Inc., *  59 Temple Place, Suite 330, Boston, MA  02111-1307  USA *///------------------// Memory Management//------------------PVOIDMemAlloc (ULONG p_Size, BOOLEAN zero){  PVOID l_Return = NULL;  if (p_Size)    {      __try      {	if (NdisAllocateMemoryWithTag (&l_Return, p_Size, 'APAT')	    == NDIS_STATUS_SUCCESS)	  {	    if (zero)	      NdisZeroMemory (l_Return, p_Size);	  }	else	  l_Return = NULL;      }      __except (EXCEPTION_EXECUTE_HANDLER)      {	l_Return = NULL;      }    }  return l_Return;}VOIDMemFree (PVOID p_Addr, ULONG p_Size){  if (p_Addr && p_Size)    {      __try      {#if DBG	NdisZeroMemory (p_Addr, p_Size);#endif	NdisFreeMemory (p_Addr, p_Size, 0);      }      __except (EXCEPTION_EXECUTE_HANDLER)      {      }    }}/* * Circular queue management routines. */#define QUEUE_BYTE_ALLOCATION(size) \  (sizeof (Queue) + (size * sizeof (PVOID)))#define QUEUE_ADD_INDEX(var, inc) \{ \  var += inc; \  if (var >= q->capacity) \    var -= q->capacity; \  MYASSERT (var < q->capacity); \}#define QUEUE_SANITY_CHECK() \  MYASSERT (q != NULL && q->base < q->capacity && q->size <= q->capacity)#define QueueCount(q) (q->size)#define UPDATE_MAX_SIZE() \{ \  if (q->size > q->max_size) \    q->max_size = q->size; \}Queue *QueueInit (ULONG capacity){  Queue *q;  MYASSERT (capacity > 0);  q = (Queue *) MemAlloc (QUEUE_BYTE_ALLOCATION (capacity), TRUE);  if (!q)    return NULL;  q->base = q->size = 0;  q->capacity = capacity;  q->max_size = 0;  return q;}VOIDQueueFree (Queue *q){  if (q)    {      QUEUE_SANITY_CHECK ();      MemFree (q, QUEUE_BYTE_ALLOCATION (q->capacity));    }}PVOIDQueuePush (Queue *q, PVOID item){  ULONG dest;  QUEUE_SANITY_CHECK ();  if (q->size == q->capacity)    return NULL;  dest = q->base;  QUEUE_ADD_INDEX (dest, q->size);  q->data[dest] = item;  ++q->size;  UPDATE_MAX_SIZE();  return item;}PVOIDQueuePop (Queue *q){  ULONG oldbase;  QUEUE_SANITY_CHECK ();  if (!q->size)    return NULL;  oldbase = q->base;  QUEUE_ADD_INDEX (q->base, 1);  --q->size;  UPDATE_MAX_SIZE();  return q->data[oldbase];}PVOIDQueueExtract (Queue *q, PVOID item){  ULONG src, dest, count, n;  QUEUE_SANITY_CHECK ();  n = 0;  src = dest = q->base;  count = q->size;  while (count--)    {      if (item == q->data[src])	{	  ++n;	  --q->size;	}      else	{	  q->data[dest] = q->data[src];	  QUEUE_ADD_INDEX (dest, 1);	  	}      QUEUE_ADD_INDEX (src, 1);    }  if (n)    return item;  else    return NULL;}#undef QUEUE_BYTE_ALLOCATION#undef QUEUE_ADD_INDEX#undef QUEUE_SANITY_CHECK#undef UPDATE_MAX_SIZE